Yahoo! Messenger (sometimes abbreviated Y!M) is an advertisement-supported instant messagingclient and associated protocol provided by Yahoo. Yahoo Messenger is provided free of charge and can be downloaded and used with a generic "Yahoo ID" which also allows access to other Yahoo services, such as Yahoo Mail, where users can be automatically notified when they receive new email. Yahoo also offers PC-PC, PC-Phone and Phone-to-PC service, file transfers, webcam hosting, text messaging service, and chat rooms in various categories.

Yahoo Messenger was originally launched under the name Yahoo! Pager on March 9, 1998.[1]

In addition to instant messaging features similar to those offered by ICQ, it also offers (on Microsoft Windows) features such as: IMVironments (customizing the look of Instant Message windows, some of which include authorized themes of famous cartoons such as Garfield or Dilbert), address-book integration and Custom Status Messages.[3] It was also the first major IM client to feature BUZZing and music-status. Another recently added feature is customized avatars. Yahoo Messenger also allows users to access Yahoo Chat Rooms. As of December 14, 2012, all public chat rooms on Yahoo Messenger have been shut down as part of a series of features being changed/added/deleted.[4][5]

As of March 27, 2016, the only supported clients are the Android, iOS and web browser clients. The legacy Windows, Mac, Linux and Solaris clients are not supported anymore, and their servers will begin shutting down on August 5, 2016,[6] with the clients no longer working by August 31, 2016.[7] It turned out that the servers for the legacy clients were finally shut down sometime between the mid-morning & early afternoon hours east coast time on September 1, 2016, resulting in the legacy desktop clients no longer being able to access their buddy/contact lists. On April 12, 2016, Yahoo announced that the messenger would support six non-English languages to bridge the language gap and create personalised experiences for its users. Yahoo Messenger will support Hindi (on Android devices only), Chinese, French, German, Spanish and Indonesian.[8] A new desktop app for Windows and Mac has been released.[9]

As of 8.0, Yahoo Messenger has added the ability for users to create plug-ins, which are then hosted and showcased on the Yahoo Plug-in gallery. Yahoo now no longer provides plugin development SDK.[12]

Yahoo Messenger users can listen to free and paid Internet radio services, using the official Yahoo Music Radio plug-in from within the messenger window. The plug-in also player functionality, such as play, pause, skip and rate this song.

Yahoo's software now allows users with the most current updated versions (messenger 8 through 10) to utilize its webcam service. This option enables users from distances all over the world to view others who have installed a webcam on their end. The service is free with provided speeds averaging from a range in between 1 and 2 frames per second. The resolution of the images can be seen starting at 320 x 240 pixels or 160 x 120.

The British intelligence agency GCHQ's secret mass surveillance program Optic Nerve and NSA are reported to be indiscriminately collecting still images from Yahoo webcam streams from millions of mostly innocent Yahoo webcam users, among other things creating a database for facial recognition for future use. Optic Nerve takes a still image from the webcam stream every 5 minutes.[13]

Yahoo Messenger's installation process automatically installs an extra uniform resource identifier (URI) scheme handler for the Yahoo! Messenger Protocol into some web browsers, so that URIs beginning ymsgr can open a new Yahoo Messenger window with specified parameters. This is similar in function to the mailto URI scheme, which creates a new e-mail message using the system's default mail program. For instance, a web page might include a link like the following in its HTML source to open a window for sending a message to the YIM user exampleuser:

<a href="ymsgr:sendim?exampleuser">Send Message</a>

To specify a message body, the m parameter is used, so that the link location might look like this: ymsgr:sendim?exampleuser&m=This+is+my+message

On October 13, 2005, Yahoo and Microsoft announced plans to introduce interoperability between their two messengers, creating the second-largest real-time communications service userbase worldwide: 40 percent of all users (AIM currently holds 56 percent). The announcement comes after years of third-party interoperability success (most notably, Trillian, Pidgin) and criticisms that the major real-time communications services were locking their networks. Microsoft has also had talks with AOL in an attempt to introduce further interoperability, but so far, AOL seems unwilling to participate.

Interoperability between Yahoo and Windows Live Messenger was launched July 12, 2006. This allowed Yahoo and Windows Live Messenger users to chat to each other without the need to create an account on the other service, provided both contacts used the latest versions of the clients. It was not possible to talk using the voice service between the two different messengers.

As of December 14, 2012, the interoperability between Yahoo Messenger and Windows Live Messenger ceased to exist.[4] The Live Messenger contacts will appear as greyed out and it will not be possible to send instant messages to them.

Yahoo Chat was a free online chat room service provided exclusively for Yahoo! users. Yahoo! Chat was first announced on January 7, 1997,[2] as it was confirmed to be a feature on the very first release of Yahoo! Pager. On March 9, 1998, the first public version of Yahoo! Pager was released, with Yahoo! Chat among its features. It allowed users to create public chat rooms, send private messages, and use emoticons.

In June 2005, with no advance warning, Yahoo disabled users' ability to create their own chat rooms. The move came after KPRC-TV in Houston, Texas reported that many of the user-created rooms were geared toward pedophilia. The story prompted several advertisers, including Pepsi and Georgia-Pacific, to pull their ads from Yahoo.[15]

On November 30, 2012, Yahoo announced that among other changes that the public chat rooms would be discontinued as of December 14, 2012.[5] quoting "This will enable us to refocus our efforts on modernizing our core Yahoo products experiences and of course, create new ones."

Until the chat rooms became unavailable on December 14, 2012, all versions of Yahoo! Messenger could access Yahoo chat rooms.

Yahoo has since closed down the chat.yahoo.com site (which is now a redirect to a section of the Yahoo! Messenger page) because the great majority of chat users accessed it through Messenger. The company is still working on a way to allow users to create their own rooms while providing safeguards against abuse. A greyed-out option to "create a room" was available until the release of version 11.

A recently added feature in Yahoo! Messenger allows users to connect with Facebook.

Yahoo Messenger users are subject to unsolicited messages (SPIM).[16][17] Yahoo's primary solution to the issue involves deleting such messages and placing the senders on an Ignore List.[18]

As of 2007[update], it was estimated that at least 75% of all users who used Yahoo chat rooms were bots.[19] Yahoo introduced a CAPTCHA system to help filter out bots from joining chat rooms, but such systems generally do little to prevent abuse by spammers.[20]

Unix - 1.0.4 - September 2003. It can still be downloaded from Softpedia.

Version 1.0.6 can be downloaded from the Unix Beta page

Yahoo released a preview version of Yahoo Messenger for Windows Vista. It had been designed to exploit the new design elements of Vista's Windows Presentation Foundation and introduced a new user interface and features. It lacked some basic functions such as webcam support. It has since been discontinued.

On November 4, 2014, the Electronic Frontier Foundation listed Yahoo! Messenger on its "Secure Messaging Scorecard". Yahoo! Messenger received 1 out of 7 points on the scorecard. It received a point for encryption during transit, but missed points because communications were not encrypted with a key the provider didn't have access to (i.e. the communications were not end-to-end encrypted), users couldn't verify contacts' identities, past messages were not secure if the encryption keys were stolen (i.e. the service did not provide forward secrecy), the code was not open to independent review (i.e. the source code was not open-source), the security design was not properly documented, and there had not been a recent independent security audit.[24][25]

In September 2016, The New York Times reported that Yahoo's security team, led by Alex Stamos, had pressed for Yahoo to adopt end-to-end encryption sometime between 2014 and 2015, but this had been resisted by Jeff Bonforte, Yahoo's senior vice president, "because it would have hurt Yahoo’s ability to index and search message data".[26]

^Perlroth, Nicole; Goel, Vindu (28 September 2016). "Defending Against Hackers Took a Back Seat at Yahoo, Insiders Say". The New York Times. Retrieved 28 September 2016. Jeff Bonforte, the Yahoo senior vice president who oversees its email and messaging services, said in an interview last December that Mr. Stamos and his team had pressed for Yahoo to adopt end-to-end encryption for everything. ... Mr. Bonforte said he resisted the request because it would have hurt Yahoo’s ability to index and search message data to provide new user services.